Viagra is Elvis in pill form: Sexy yet safe, maker of corporate millions, the undisputed king. Doctors have scribbled 133 million Viagra prescriptions since Pfizer launched the pill in 1998, and sales in 2002 alone reached $1.7 billion. So it's no surprise that other companies want a slice of the impotence pie. There's an anti-impotence nasal spray in the works, and candy maker Wrigley recently received a patent for anti-impotence gum. (Don't rush to the vending machine just yet: It's years away.) The biggest developments are two new Viagra-like pills Bayer's and GlaxoSmithKline's Levitra (vardenafil), approved by the FDA in August, and Eli Lilly's Cialis (tadalafil), which is close to being on the market. Drug companies are also feverishly developing treatments for the estimated 43 percent of women who suffer some degree of sexual dysfunction (in fact, one of the most promising treatments for women is a surprise (Viagra).